1. Technical Field of the Invention
The invention includes a medical device and more specifically to a valve found generally within a frame. In preferred devices the frame is comprised of a radially expandable stent which can be delivered through a delivery device such as a catheter.
2. Background of the Invention
Lower extremity venous hypertension in addition to venous insufficiency is a major cause of morbidity in the United States. Symptoms of venous disease include lower extremity edema, varicosities, skin pigmentation changes, skin ulceration, and general poor circulation. One solution to this problem is to replace the defective valve or the vein with a valve assembly.
Current valves include a pressure responsive, pressure directed ball movement valve assemblies. The problem with mechanical ball valves is that mechanical valves are susceptible to clot formation. Additionally, there are problems associated with long-term wear and tear on the device.
Artificial valves such as biological valves are also known. Biological valves include homografts, allografts, and xenografts. Problems associated with some biological valves include the supply of the valves, immunity response, or problems associated with matching the size with the donor.
Finally other problems associated with valve repair include placement problems in which the device cannot be repositioned once it is ejected from the placement catheter, leakage that occurs, around the valve, and emboli formation.
In light of this background, there remains a need for alternative and improved devices and methods for providing valvular function within vessels of the body. The present invention is addressed to these needs.